Sequelize - subquery in where clause

Question

I'm using Sequelize in my Express app. I need to generate a query that has a subquery in the WHERE clause.

SELECT *
  FROM MyTable
 WHERE id NOT IN (
       SELECT fkey
         FROM MyOtherTable
        WHERE field1 = 1
          AND field2 = 2
          AND field3 = 3
       )

I first tried relations/associations through my models but couldn't get it to work. Something like:

MyTable.find( {
    where: {
        id: {
            $notIn: // <= what goes here? Can I somehow reference my include model?
        }
    },
    include: [ {
        model: MyOtherTable,
        where: {
          field1: 1,
          field2: 2,
          field3: 3
    } ]
} );

Then I tried using Sequelize.where(), no luck there.

Then I tried Sequelize.literal() and that works but not sure if it's a "proper" way of doing a subquery in a where clause in Sequelize as I'm new to it.

MyTable.find( {
    where: {
        id: {
            $notIn: sequelize.literal( 
                '( SELECT fkey ' +
                    'FROM MyOtherTable ' +
                   'WHERE field1 = ' + field1 +
                    ' AND field2 = ' + field2 +
                    ' AND field3 = ' + field3 + 
                ')'
        }
    } 
} );

I also know that I could use Sequelize.query() but don't really know if I should reach for it or if literal()is the right away as I feel like there's something I'm overlooking.

I would really like to know how to perform a subquery in a WHERE clause with Sequelize the "proper" way.

Thanks for the feedback!

Answer 1

I have encountered a similar issue in my project. The way I choose to implement it is a bit different for two reasons:

1. If at one point in time Sequelize decides to implement sub queries - the syntax is ready.
2. Use Sequelize protection against SQL injection.

Here is my code snippet, hope it helps.

Sequelize v5

const tempSQL = sequelize.dialect.QueryGenerator.selectQuery('MyOtherTable',{
    attributes: ['fkey'],
    where: {
          field1: 1,
          field2: 2,
          field3: 3
    }})
    .slice(0,-1); // to remove the ';' from the end of the SQL

MyTable.find( {
    where: {
        id: {
              [Sequelize.Op.notIn]: sequelize.literal(`(${tempSQL})`)
        }
    } 
} );

Sequelize v6

const tempSQL = sequelize.dialect.queryGenerator.selectQuery('MyOtherTable',{
    attributes: ['fkey'],
    where: {
          field1: 1,
          field2: 2,
          field3: 3
    }})
    .slice(0,-1); // to remove the ';' from the end of the SQL

MyTable.find( {
    where: {
        id: {
              [Sequelize.Op.notIn]: sequelize.literal(`(${tempSQL})`)
        }
    } 
} );

Some people might choose to not use the tempSQL variable and simply build the SQL inside the find structure (maybe using a helper method?)

I also think this might be the basis for a sub queries extension for sequelize as it uses the same syntax almost.

Answer 2

In addition to @Shahar Hadas answer, because i fall into some errors using the code he showed.

Here is a more complexe example. In this example we have a main table named "Artist" in a Many-to-Many relationship with "Tag". "Tag" are associated to a predefined list of tags i named "TagType". We want to fetch all Artists linked to all the searched tags (TagType Id).

const tagsSearched = [1, 2];

const subQueryOptions = {
    attributes: ['id'], // You have to list at least one attribute
    include: [
        {
            model: models.Tag,
            required: true,
            attributes: [], // Avoid the only_full_group_by error
            through: {
                attributes: [], // Avoid the only_full_group_by error
            },
            include: {
                model: models.TagType,
                required: true,
                attributes: [], // Avoid the only_full_group_by error
                where: {
                    id: {
                        [Op.in]: tagsSearched, // Array of tags searched
                    }
                },
            },
        }
            ],
    group: sequelize.col('artist.id'), // Group by the main parent ID of this query
    having: sequelize.where(sequelize.fn('count', 
            sequelize.col('tags.tagType.id')), {
                [Op.gte]: tagsSearched.length,
    }), // Get only the artists that have at least the "tagsSearched" associated
}

// Parse the subQueryOptions, this operation would serialize the queryOptions
Model._validateIncludedElements.bind(models.Artist)(subQueryOptions);

// First argument has to be a string (table name, by default in plural)
// Second argument is our serialized query options
// Third argument is the model used
const artistsSubQuery = sequelize.dialect.queryGenerator.selectQuery("artists", subQueryOptions, models.Artist)
.slice(0,-1); // to remove the ';' from the end of the SQL query

models.Artist.findAll({
    where: {
        id: {
            [Op.in]: sequelize.literal(`(${artistsSubQuery})`),
        }
    }
});

I will update this in case of questions.